Ford 2003 Mustang Workshop Manual page 3742

Is the voltage greater than 10 volts?
H14 CHECK INPUT TO THE ICM
Connect: Rear Window Defrost Switch C241.
Depress the rear window defrost switch to ON.
Measure the voltage between ICM C220a pin 9, circuit 175
(BK/YE), harness side and ground.
Is the voltage greater than 10 volts?
H15 CHECK CIRCUIT 175 (BK/YE) FOR AN OPEN
Key in OFF position.
Measure the resistance between ICM C220a pin 9, circuit
175 (BK/YE), harness side and the rear window defrost
switch C241 pin 2, circuit 175 (BK/YE) , harness side.
Is the resistance less than 5 ohms?
H16 CHECK THE ICM FOR CORRECT OPERATION
Disconnect all ICM connectors.
Check for:
corrosion
pushed-out pins
Connect all ICM connectors and make sure they seat
correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
Yes
GO to H16 .
No
GO to H15 .
Yes
INSTALL a new rear
window defrost switch.
REFER to Rear Window
Defrost Switch in this
section. TEST the system
for normal operation.
No
REPAIR the circuit. TEST
the system for normal
operation.
Yes
INSTALL a new ICM.
REFER to Section 413-01
CLEAR the DTCs.
REPEAT the self-test.
No
The system is operating
correctly at this time.
Concern may have been
.